Download Mathemagic!!

Mathemagic!!
Cheryl Miner
Nebraska Wesleyan University
[email protected]
Binary Magic
• Pick a number 1 – 64
• Which number cards does your number
appear?
Think of a Number
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Think of a whole number
Multiply by 2
Add 6
Add the square of your original number
Subtract 5
Take the square root of your answer
Tell me the answer
Your original number is: _______
Divining Two Numbers
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Volunteer rolls a pair of dice
Multiply the number on top of one die by 2
Add 3 to this.
Multiply by 5
To this result, add the number on top of the 2nd die
Multiply this sum by 10
Tell me the result & I’ll tell you the two numbers rolled!
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Select a number
Double it
Add 6
Divide by 2
Subtract your original number
Your number is 3
Any algebraic identity may be used as the basis of
a number game.
2
2
(5 x)  (12 x)
 13
2
x
Create your own trick for the equation:
(3x) 2  (4 x) 2  15
 x3
5
Who’s Hiding the Coin
• 2-9 volunteers & assign number to each person
• Turn your back & have someone in group hide a coin in
his/her left or right hand
• Have someone
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Multiply the number of person concealing coin by 2
Add 5
Multiply by 5
Add 10
Add 1 if the coin is in the right hand or
Add 2 if the coin is in the left hand
– Announce the result
• Identify the person holding the coin and in which hand!
Who’s Hiding the Coin
• 2-9 volunteers & assign number to each person
• Turn your back & have someone in group hide a coin in his/her left
or right hand
• Have someone
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Multiply the number of person concealing coin by 2
Add 5
Multiply by 5
Add 10
Add 1 if the coin is in the right hand or
Add 2 if the coin is in the left hand
– Multiply by 10
– Add 1 for penny, 2 for nickel, 3 for dime, 4 quarter, 5 for half dollar, 6 for
dollar
– Announce the result
• Identify the person holding the coin and in which hand!
12345679
The Missing 8
• Write down 12345679
• Volunteer: Place an “x” over the digit that
you like the least
• Multiply 12345679 by a number
Answer: product will have all digits which
match the number marked with the “x”
Gopher Magic
http://www.learnenglish.org.uk/games/magic
-gopher-central.swf
Missing Digit
1.
2.
3.
4.
5.
6.
Pick a 5-digit number & multiply by 9
Write down the resulting number
Choose any digit (except zero) and circle it.
Find the sum of the remaining digits.
Tell me the sum.
Your missing digit is: _________
The Magic of 8
• Multiply your phone number (without its area
code) by the number 8
• Write down:
– The product from step 1
– Your 7-digit phone number
–8
• Add all the digits in 3 numbers
• If the sum is more than 1 digit, then add the
digits in the sum. Continue adding up digits until
only one digit is left.
49 - Lucky Number Cubes
• Find the following products:
Top of Red * Top of White
Bottom of Red * Bottom of White
Top of Red * Bottom of White
Bottom of Red & Top of White
• Add the results